1. Field of the Invention
This invention relates to pole-mounted tools of the type employed to prune tree branches and the like.
2. Description of the Prior Art
Tree pruners conventionally comprise a pair of coacting cutting jaws, one being pivotally movable in relation to the other to effect a cutting action. The movable jaw is connected to a lever arm carrying a sheave. The sheave is located at a fixed radial distance from the pivot axis of the movable jaw. A rope is threaded around the sheave to provide a means of operating the tool from a remote location, e.g., at ground level when the tool is carried on the end of a pole and used to cut branches at an elevated location.
The fixed radial distance between the sheave and the pivot axis of the movable jaw provides a predetermined mechanical advantage which assists cutting. Experience has indicated that this mechanical advantage usually is adequate to effect cutting of a certain range of branch sizes, but is sometimes inadequate to effect cutting of larger branches. The cutting capacity of the tool can be increased by providing a longer level arm. However, as the length of the lever arm is increased, the tool becomes more cumbersome and difficult to handle, particularly when attempting to cut smaller sized tightly congested branches.
Thus, those skilled in the art have deemed it necessary to strike a compromise between cutting capacity and tool maneuverability, with neither being optimized to the fullest extent possible.